Looks like the API call URL has been changed, as it's now called “Intent APIs”. Check DNAC API doc for DNAC v1.2.6 for more info.

For eg. Line 76 on dnac-nbapi-hello-world.py should be changed to the following - to represent the changes and match the official documentation:

    return "https://%s:%s/dna/intent/api/v1/%s" % (controller_ip, DNAC_PORT, path)